Vaccines, injectable medications and other injectable therapeutic fluids are often delivered to a physician, nurse or other medical technician in glass or plastic vial. The opening of a vial is typically sealed with a rubber or silicone septum. The septum and opening end of the vial are then sealed with metal foil or another removable cap. This type of vial configuration was developed for use with typical hypodermic needle syringes. Therefore, the technician administering the injection pierces the rubber septum with the hypodermic needle prior to filling the syringe. Piercing the septum places the lumen of the needle into fluid communication with the injectable content of the vial, which may be withdrawn into the syringe and subsequently injected into a patient.
Vials for injectable substances are available in a variety of sizes. Certain vials are sized such that the quantity of injectable fluid is suitable for a single injection only. These vials are often referred to as single-use vials. In recognition of the fact that it is difficult or impossible to successfully withdraw the entire quantity of injectable fluid from a vial, single use vials cause substantial vaccine or injectable fluid waste. Therefore, there is a trend in health care to provide vaccines and other injectable substances in multi-dose vials to minimize waste. Multi-dose vials can substantially reduce the cost of an inoculation campaign. For example, the World Health Organization reported in April, 2012 that the price of a hepatitis B vaccine was approximately $0.2 per dose for a 10 dose vial compared to approximately $0.4 per dose when the vaccine was provided in one-dose vials.
One challenge presented by the use of multi-dose vials is the need to maintain a sterile seal over the contents of the vial in between the withdrawal of subsequent doses. Dose-to-dose sterility may be accomplished with a conventional needle-based injection system without substantially modifying a conventional rubber septum vial configuration. Since a hypodermic needle has a sharp point and a relatively thin cross section, and because the vial septum has substantial thickness, the septum tends to self-seal as a hypodermic needle is withdrawn. Therefore, multiple needle insertions into a multi-use vial may be accomplished to withdraw multiple doses, provided care is taken not to compromise the structural integrity of the vial septum.
Although needle-based injection systems are relatively easy to fill from standard vials, needles present certain problems when an injection is made into a patient. Therefore, various types of apparatus have been developed which provide for needle-free injections. The advantages of needle-free injection devices have been recognized for some time. Some of the advantages of needle-free devices and methods include the absence of a needle which can intimidate a patient and also present a hazard to healthcare workers. In addition, needle-free injection may decrease the risk of cross-contamination between patients.
Since a needle-free injection syringe does not employ a needle which could be used to pierce a vial septum, special challenges are presented when filling a needle-free syringe from a conventional vial of injectable substance. The challenges presented when filling a needle-free syringe from a conventional vial/septum system are particularly acute when utilizing a multi-dose vial as the vaccine source.
The embodiments disclosed herein are directed toward overcoming one or more of the problems discussed above.